I'd direct you to a website for more info, but it may be blacked-out. A few details from Wikipedia:

In January 2012, Reddit announced plans to black out its site for twelve hours on January 18, as company co-founder Alexis Ohanian announced he was going to testify to Congress. "He’s of the firm position that SOPA could potentially 'obliterate' the entire tech industry," Paul Tassi wrote in Forbes. Tassi also opined that Google and Facebook would have to join the blackout to reach a sufficiently broad audience. Other prominent sites that are reported to be participating in the January 18 blackout are Cheezburger Sites, Mojang, Major League Gaming, and Boing Boing.

Wider protests have been considered and in some cases committed to by major internet sites, with high profile bodies such as Google, Facebook, Twitter, Yahoo, Amazon, AOL, Reddit, Mozilla, LinkedIn, IAC, eBay, PayPal, Wordpress and Wikimedia being widely named as "considering" or committed to an "unprecedented" internet blackout on January 18, 2012.

On January 17 a Republican aide on Capitol Hill said that the protests were making their mark, with SOPA having already become "a dirty word beyond anything you can imagine."